The structures of building, vehicles, devices and other objects may be subjected to mechanical stresses and vibrations. For example, the engines of vehicles may vibrate on ignition. Similarly, the structures of buildings may encounter stresses and vibrations due environmental factors. Furthermore, various devices such as earthquake measuring instruments may use the vibrations and tensions in various mechanical elements as mechanical inputs to calculate the intensity and other characteristics of the earthquake.
Typically, various types of sensors are used to measure the stress or tension and vibrations on the structures. It is well known that there is a change in electrical resistance of a piezoresistive material when a mechanical stress is applied. Therefore, piezoresistive elements may be used in electrical circuits to determine the change in electrical characteristics such as voltage and current, due to the change in resistance. An existing technique as disclosed in U.S. Pat. No. 6,640,644 assigned to Delphi Technologies, uses sensors such as piezoresistors to measure the tilt and running status of a vehicle engine. However, the technique is limited to one dimensional determination that includes either tilt or running status of the vehicle engine. Therefore, the technique may not be able to determine the value of tilt when the engine is running.
U.S. Pat. No. 5,206,449 assigned to Richard McClish, discloses the use of peizoresistive transducer to determine the vibrations of the strings of a guitar. However, this technique is limited to determination of vibration characteristics and can not be used to determine the tension as well. Another technique disclosed in U.S. Pat. No. 5,099,742 measures tensions in strings by compressible electrically conductive member. However, this technique is limited to determination of tension in the string and can not be used to determine the vibrations as inputs.
Therefore, the techniques are desirable for effective determination of the mechanical inputs.